Residual sleepiness in sleep apnea patients treated by continuous positive airway pressure

Hypoxic brain damage might explain persistent sleepiness in some continuous positive airway pressure-compliant obstructive sleep apnea called residual excessive sleepiness. Although continuous positive airway pressure may not be fully efficient in treating this symptom, wake-promoting drug prescription in residual excessive sleepiness is no longer allowed by the European Medicines Agency. The aim of this study is to describe residual excessive sleepiness phenotypes in a large prospective sample of patients with obstructive sleep apnea. Residual excessive sleepiness was defined by an Epworth Sleepiness Scale score ≥ 11. Eligible patients from the French National Sleep Registry attending follow-up continuous positive airway pressure visits numbered 1047. Patients using continuous positive airway pressure < 3 h (n = 275), with residual apnea-hypopnea index > 15 h⁻¹ (n = 31) or with major depression were excluded (n = 150). Residual excessive sleepiness prevalence in continuous positive airway pressure-treated obstructive sleep apnea was 13% (18% for those with an initial Epworth Sleepiness Scale score > 11), and significantly decreased with continuous positive airway pressure use (9% in ≥ 6 h night⁻¹ continuous positive airway pressure users, P < 0.005). At the time of diagnosis, patients with residual excessive sleepiness had worse subjective appreciation of their disease (general health scale, Epworth Sleepiness Scale and fatigue score), and complained more frequently of continuous positive airway pressure side-effects. Residual excessive sleepiness prevalence was lower in severe obstructive sleep apnea than in moderate obstructive sleep apnea (11% when AHI > 30 h⁻¹ versus 18% when AHI 15-30, P < 0.005). There was no relationship between residual excessive sleepiness and body mass index, cardiovascular co-morbidities or diabetes. Continuous positive airway pressure improved symptoms in the whole population, but to a lower extent in patients with residual excessive sleepiness (fatigue scale: -5.2 versus -2.7 in residual excessive sleepiness- and residual excessive sleepiness+ patients, respectively, P < 0.001). Residual excessive sleepiness prevalence decreased with continuous positive airway pressure compliance. Hypoxic insult is unlikely to explain residual excessive sleepiness as obstructive sleep apnea severity does not seem to be critical. Residual symptoms are not limited to sleepiness, suggesting a true 'continuous positive airway pressure-resistant syndrome', which may justify treatment by wake-promoting drugs.

Endothelial function in patients with post-CPAP residual sleepiness

STUDY OBJECTIVES

The significance of residual excessive daytime sleepiness (EDS) on cardiovascular markers in patients with adequately treated obstructive sleep apnea (OSA) remains unclear. The objective of this study was to investigate flow-mediated dilatation (FMD) and inflammatory markers (C-reactive protein [CRP], tumor necrosis factor [TNF]-alpha, and interleukin [IL]-6) in continuous positive airway pressure (CPAP)-compliant patients with residual EDS compared with CPAP-compliant patients without residual EDS.

METHODS

FMD of the brachial artery was measured by ultrasound in 12 CPAP-compliant patients with OSA who had residual EDS and 12 age-, sex-, and body mass index-matched CPAP-compliant patients with OSA who did not have residual EDS on week 8 after initiation of CPAP. Twelve otherwise-healthy subjects without sleep disordered breathing were used as control subjects. Serum concentrations of CRP, TNF-alpha, and IL-6 were quantified by enzyme-linked immunosorbent assays.

RESULTS

Baseline FMD was comparable among CPAP-compliant patients with residual EDS (7.2 +/- 2.3), CPAP-compliant patients without residual EDS (8.6 +/- 2.1), and control subjects (7.7 +/- 1.4) (p = 0.37). The concentrations of CRP, TNF-alpha, and IL-6 were also not significantly different between subjects with CPAP-compliant residual EDS and those without residual EDS (p = 0.44, p = 0.37, and p = 0.42; respectively).

CONCLUSIONS

Residual EDS in patients with adequately treated OSA may not represent a risk factor for cardiovascular diseases.

Modafinil improves functional outcomes in patients with residual excessive sleepiness associated with CPAP treatment

OBJECTIVES

The objective of this secondary analysis was to examine the effects of modafinil on the Functional Outcomes of Sleep Questionnaire (FOSQ) in patients with obstructive sleep apnea and residual excessive sleepiness with continuous positive airway pressure (CPAP) use. We also explored the association of improvement of functional status with the presenting level of subjective sleepiness.

METHODS

Data were pooled from 2 randomized placebo-controlled studies (4-week and 12-week interventions) of modafinil in patients with residual sleepiness (Epworth Sleepiness Scale score > or =10 on CPAP).

RESULTS

The analysis included 480 patients (FOSQ efficacy data n=442 patients), 292 in the modafinil group and 188 in the placebo group. The mean age (SD) of the analyzed sample was 49.7 (9.2) years; 76% were men. Following administration with modafinil, there were greater improvements from baseline in the Total score (p < 0.0001) as well as 4 of the 5 domains (p < 0.05), compared with placebo. A greater proportion of patients who received modafinil were considered responders, compared with patients who received placebo (45% vs. 25%; p < 0.001). Responder analysis based on the individual FOSQ domain items demonstrated that 18 of the 30 FOSQ items increased by at least 1 point for significantly more patients who received modafinil (p < 0.05). Improvements in functional status were not found to depend on patients' degree of subjective sleepiness at baseline.

CONCLUSION

In this secondary analysis of data from patients with OSA and excessive sleepiness despite CPAP use, modafinil was associated with improvements in patients' functional outcomes and their ability to engage in a broad array of everyday activities.